Calculation of Sediment Delivery from the Guadiana Estuary to the Coastal

Abstract

Astudy has been conducted to provide updated estimates (period 1980-2000) of the transfer of sedimentary material from the Guadiana river (SW Europe) to the coastal ocean, focusing on the role played by the estuarine system. The discharge of fine suspended sediment from the river to the estuary has been calculated based on measured data and compared with previous estimates. Numerical models of cohesive and non-cohesive sediment transport have been used to provide order of magnitude estimates of sediment fluxes from the estuary to the continental shelf for different freshwater flow scenarios. Episodic flood events play a crucial role in the discharge of sediment from the Guadiana river to the coastal ocean. Apparently, the estuary retains only a minor share (about 10%) of the total amount of finegrained sediment produced in the drainage basin, which is presently estimated at 0.5-1.5 x 10 t year . Based on the calculation of sediment transport capacities, it is estimated that the order of magnitude of the transfer of sand from the estuary to the coastal region is 0.1 x 10 m year , which seems in agreement with the recent pattern of shoreline